US418821A - smith - Google Patents

Description

(No Model.) 4 Sheets-'Sheet 1.

J. D. SMITH GAS ENGINE.

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4, Sheets-Sheet 2.

i (No Model.)

' J. D. SMITH.

- GAS ENGINE. 7 No. 418,821 Patented Jan. 7, 1890.

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(No Model.) 4 Sheets Sheet 3.

J. DQSMITH.

v GAS ENGINE; I No. 418,821; Patented Jan. 7, 1890.

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\ WITNESSES nfPz'rzns. Phuwunmmphu, Washington. D. c.

(No Model.) I

- J. D. SMITH;

' GAS ENGINE. v

. Patented Jan. 7, 1890.

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A UNiTnD ST TES PATENT OF IC JAMES DOWNEB SMITH, OF, PHILADELPHIA, PENNSYLVANIA, ASSIGNORQF ONE-HALF TO JOSEPH L. FERRELL, OF SAME PLACE.

GAS-ENGINE.

- SPECIFICATIQN forming part of Letters Patent No. 418,821, dated January V, 1890.

l Application filed April 18, 1885. lserial No. 162,624:- (No model.) d

To all whom it may concern.-

,have invented certain new and useful Improvements in Gas-Engines.

The following is a specification of my said improvements, reference being had to the acc'ompanying drawings, wherein IO the complete engine as seen from the oppositesides. Fig. 3 is a top or plan view thereof, and. Fig. 4 an end view thereof. Fig. 5 is a central vertical section through the axis of the motor-cylinder and adjacent parts on an I 5 enlarged scale. Fig. 6 is a horizontal section through the ignition-chamber and the valve by which it communicates with the motorcylinder. Fig. 7 is a vertical section on the irregular line to w of Fig. 5. Fig. 8 is an exterior end View of the motor-cylinder. Figs. 9

and 10 are sectional views (on a much enlarged scale) of the ignition-valve at different points. Fig. 11 is a vertical section through the center of the passages by which air and gas are admitted to the motor-cylinder, the scale 'ofthis and the succeeding figures being still further enlarged. Figs. 12, 13, and 14 are horizontal sections on the lines 2 z, y y, or m, respectively, of Fig. 11.j..'Fig. 1.5 is a view,

partly in section, of the valve which is controlled by the governor of the engine. My improvementsare especially adapted for use in connection with that class of gasengines in which the charge is compressed be- 3 5 fore ignition, although some of them are applicable to engines of different types.

Their nature and objects can be best explained in describing the construction and operation of the several parts.

Referring to the general exterior view of the engine, A represents the bed supporting the motor-cylinder B, which is surrounded with the usual water-jacket, the water-circulation being maintained by means of pipe O is the connecting-rod of the motor-piston; D, the iiy-wheel; E, the rod for operating the valve mechanism, which rod is actuated by an eccentric mounted upon the'main 5o'driving-sl1a'ft in the usual manner.

The charge is supplied to the motor-cylinder by a pump, whose cylinder-is shown at J, and which is worked by means of a connecting-rod X, attached to a wrist-pin radially adjustable in a disk D, mounted upon the driving-shaft.

K is a governor which controls in a mani nerto be hereinafter explained the ext'ent of Figures 1 and 2 areviews in elevation of v the charge introduced into the motor-cylinder.

N is a strong receptacle, into which under certain conditions the surplus charge is forced by the action of the pump, and which for that purpose connects with the pump-cylinder J by a pipe P.

The igniting system is contained in an end extension B of the motor-cylinder B, by which the charge is conveyed from the pump-cylinder J to the motor-cylinder B and ignitingchamber.

Y, Figs. 2 and 4, indicates the main inletpipe, which is connected with the gas-supply, and G is the discharge-pipe leading from a large chamber F, into which the direct exhaust from the motor-cylinder takes place. i

The general operation of the apparatus is as follows: A charge of mingled air and gas is pumped intothe motor-cylinder ata time when the motor-piston is at or near the outer end of its stroke. WVh en the piston has been brought to its innermost position, said charge is ignited, driving the piston forward and actuating the driving-shaft. This movement opens the exhaust-valves and permits the discharge of the products of combustion into the exhaust-chamberF, and thence into the open air. In the meanwhile the return-stroke of the engine actuates the pumping mechanism, so that a fresh charge'is delivered into the cylinder and the operation is repeated.

Having thus given a most general descrip- 0 tion of the operation of the machine, I will now proceed to a detailed description of those portions wherein the present improvements consist. Thev motor-cylinder and adjacent parts are shown in vertical section in Fig. 5. 9 5 The interior shell R of the cylinder surrounded by the water-jacket terminates in a conical compression-chamber 0%, into which the inlet-passage n for the charge of air and gas leads.

As will be seen in the drawings, I00

this inlet directs the current of entering gas and air upward, so as to impinge upon the upper surface of the shell R, the passage being preferably inclined, as shown. Beneath the inlet n is a downwardly-depending chamber L, partly surrounded by a water-jacket and communicating at 0 with the interior of the motor-cylinder. At the bottom of this chamber L is the exhaust-valve t, the actuat ing mechanism of which will be seen on referrin g to Fig. 1, but which will be hereinafter described in connection with the description of the other valve movements. W'hen open, the exhaust-valve conununicates with the large exhaust-chamberF, whose construction and functions will also hereinafter be described.

The operation of the parts now under consideration is as follows: The charge of gas and airis introduced into the cylinderthrough the orifice n and fills both the cylinder proper and the chamber L. The piston 7t being brought to its extreme innermost position, the charge is compressed into the chamber m,and is then ignited in a manner which will be hereinafter described. The ignition commences at the point I in Fig.5, and primarily takes place in the conical chamber m of the cylinder proper. By reason, however, of the extended chamber L the combustion of the whole charge is not instantaneous, but takes placefirst in the compression-chamber m and subsequently throughout the chamber L. This method of protractiug the combustion has the advantage of relieving thepiston from a too sudden shock and is found to economize the actual force of the charge in the best manner. Assuming that combustion has taken place (the inlet valve 19 being of course closed) and that the piston it has been driven to its extreme outward position, the exhaustvalve t is opened and the products of com: bustion rush out into the exhaust-chamber F. The piston 7t" then commences its returnstroke and the exhaust-valve t remains open for a minute fraction of said return-stroke. it the same time the inlet-valve p isopened, and, owing to the direction given to the entering current at n, it flows into the cylinder above the products of combustion, which are still passing out through the orifice 0. The cylinder proper is first filled, and finally the chamber L. Thus the admission of the new charge, following the exit of the products of combustion closely, aids'in expelling more completely the residuum of the previous charge. The features of improvemcntin this connection are, therefore, the inlet-passage with an upward projection in the cylinder, the subjacent discharge passage, and the chamber L, which forms both a supplemental combustion-chamber and a portion of the discharge-passage.

The next group of features to which my invention relates, and which may properly be described at this point, are the exhaust devices. I provide a horizontal pipe G, leading from the exhaust-valve 6 into a large ex-.

haust-chamber F. This chamber F has a pipe G, which communicates with the open air. The outer end of said pipe is provided with a case H, in which is seated a puppetvalve 71, opening outward. This valve h is intended to permit the discharge from the exhaust-chamber and to close it against admission of the outside air. The interior of the exhaust-chamber, as well as a portion of the pipe G, is provided with a water-spraying device I, by which water is constantly injected upon the issuing products of combustion, the surplus water being discharged at the bottom through the drip-pipe Z. I have found that this method of constructing the exhaust-connection reduces the volume to be expelled, and by producing a partial vacuum within the chamber F gives a softer exhaust. It also prevents theignition of accumulations of unburned mixture, which sometimes occur in the exhaust-passages, owing to missed ignitions in the cylinder or to defective adjustments of the valves. The features of improvement therein are the combination, with the exhaust-valve, of an enlarged exhaustchamberand discharge-pipe leading from said chamber to theair; also the valve controlling the orifice of said exhaust-pipe against backfiow of air and the arrangement of a spraying device within said exhaust chamber,

The next group of devices to be considered comprises the igniting devices" and parts adjacent thereto; In Fig. 6 is shown a horizontal section through this portion of the apparatus. It will be seen that the chamber mot the motor-cylinder connects at its extreme end by means of a horizontal passage 1 with a small chamber a situated within the extension B of the motor-cylinder. Communication betweenthis chamber 11, (which I term the ignition-chamber) and the compres sion-chamber m is controlled by means of the valve V. This valve is in the form of a spindle, preferably tapering, having a transverse opening or port 2, arranged to register with the-passage 1, and which I term the ignitingport. Vhen the valve-spindle V is in the position shown in Fig. 6, communication between the ignition-chamber 'u, and the compression-chamber m is out off. \Vhen, however, the valve-spindle V is turned at right angles to the position there shown, the two chambers u and m communicate through the igniting-port 2. The valve movementis preferably such as to rotate the valve-spindle always in the same direction,and thus for each complete rotation of said spindle the port is opened twice. The movementof the spindle may, however, be oscillatory upon its axis instead of rotatory.

In addition to the ignition-port 2, the valvespindle has a supplemental port 5 (see Fig. 10) for the following purpose: Referring to Fig. 6, it will be seen that a very small passage-way 3 extends from the rear portion of the chamber m to the spindle V and continues on jam other side of said spindle until it; reaches the igniti'on-chamber u, its orifice at this point'be'in'g covered by a perforated plate? 22. (Shown more clearlyin Fig. 11.) The func-I tion of this passage-way 3 is to permit a small ;qu antity of mixture to pass through for the; purpose of blowing the ignition-chamber clear of the products of, combustion left from the? preceding charge.

opening of the igniting-port 2, and it is also It is necessary that this; should be accomplished in advance of the necessary that the admission of the'mixture'g through said ports should be so conducted;

The arrangement In order to clear the i nition-chamber at the proper time with relation to the opening of the igniting-port 2, I- construct the supplemental'port (see Fig. 10) in: the following manwhere it will there be seen that as the spindle nerz Said Fig. 10 represents a transverse section of the spindle V on a; line through the adjacent passage 3. It will be seen that a 7 small transverse passage is formed through the spindle V at 5, and'thata portion of the periphery of the spindle adjacent to each end of said passage5 is cut away, shown at 4.

The opening thusformed'constitutes the supplemen't'al port, and its relation to the main port 2 is shown in 'Fig'. Q'bythe dotted lines,

V rotates the supplemental port is opened a short ti-mein advance of the main port 2.

Thus in Fig. 9 the main port 2" is about to be opened; but for a short time prior to this the passages 4 and 5 of the supplemental port have established communication through the passage 3. During the time that the port 5 has thus been opened a small stream of gas and air has been discharged i'nto'the ignitionvchamber 'u, through 'thejoerforated plate 22,

driving before it the products of combustion from the previous chargeof the ignition-chamher in the following manner; At the end of the ignition-chamber u farthest from the inlet 22, I provide" a small passage-way 6. In the enlarged port-ion 25 ofthe Valve-spindle V are arranged two ducts 31, leading to a diametrical passage q. "(Indicated by dot- At each half-rotation of said spindle these ducts communicate with ted lines in Fig- 6.)

an outlet-passage '6, leading from the end of the ignition-chamber'fu, and thus immediately after the ignitionof the gases has taken place and themain' port 2 has closed -the rotation of the valve-spindle V opens an exhaust at that end of the ignition-chamberwhich is fartliest from the inlet 22. An opening 35' is formed inthe casing of the'enlarged portion 25 opposite to the points at which the passage q comes to rest on each half-rotation. The result of this arrangementi's, that the entering gases at 22 drive before them the products of combustion of the old charge.-

stant-state of incandescence. When the'ig-' nition-chamber u is sufficiently charged with the combustible mixture,ignition takes place, and the flame communic'atesthrough the portn and the passage-way 1 into the cylinder,

Where it ignites the main charge, as has been before described. Besides affording a pro tection against the backing of flame, asbefore stated, the perforated plate 22 breaks up the entering current and obviates the risk of v cooling down the incandescent loop, which might take place if the current were directed upon it with full force.

In Figs. 6 and8 a sight-glass is shown in the cap 29, that covers'the ignition-chamber. A hole 30 is piercedthrough the cap and the outer end of the hole is enlarged. -The bottomof this enlarged portion forms a seat for a glass disk 28, the remainingportion of the enlargement being threaded to receive a hollow cylinder, also threaded on its'exterior, by which the glass disk is secured in place. The object of this sight-glass is to provide means of viewing the flame as ignition takes place, since the color of the flame affords'the best indication'of correct proportions of air and gas mixture for perfect combustion. The features of improvement most prominent inthis group of devices are as follows: the construction of the Valve which controls the ignition-port in the form of a rotating spindle. Great difficulty has been heretofore experienced in operating the slide-valves ordinarily used for this purpose, since they are exposed to the full shock of the. explosion and rapidly deteriorate. I have found that ICC the u'seof a rotating spindle exposes a mini- I mum of valve-surface to the action of the flame, andthat such Wear as does take place from said exposure is regular and self-compensating. By combining in the same spindle with the igniting-port proper the secondary port for allowing what may be termed the leakage of the charge into the ignitionchamber and the exhaust-port therefrom I drive out the products of combustion in the I precise relation which is necessary to the opening of the igniting-port, and, furthermore, I obtain all of these three valve movements by a simple rotary movement of the spindle. The angular relation of thesevarious ports in the Valve-spindle V is'indicated inthe drawings, and can be of course varied to suit the conditions desired upon any particular engine without changing the principle of operation.

.The next group of (levices'compriies the valve movements of this portion of the apparatus.

Referring to Fig. 1, it will there be seen that the eccentric-rod E oscillates a toothed sector U, the teeth of which engage with a gear 6, mounted upon the projecting stem f of the spindle V. This gear is provided with a pawl, which engages with a double ratchet-tooth secured to the projecting end of the stem f. Thus as the sector U oscillates it moves the gear 6 and its pawl alternately in opposite directions, and at each complete reciprocation turns the stem f (by means of the ratchet-tooth) a half-rotation. Upon the sector U is pivoted a tripping-pawl a. At each descent of this pawl a it strikes a lever-armT and raises the link S by means of said lever T. This link S is connectedv with a horizontal link R, which is pivoted to therigid bracket Q, As the pawl 00 in its descent trips the lever T, the link S raises the end of the horizontal link R and falls again after the passage of the pawl abeyond the lever T. On the return movement of the sector the pawl turns upon its pivot, so as to pass the lever-arm T, and then drops again, by reason of its weighted rear end, into the position shown in Fig. 1. The downwardly-projecting stem at of the exhaust-valve t rests upon the horizontal link R, and each time that said link R is raised the exhaust-valvet is opened and kept open until the pawl a passes the leverT. The lower end of this stem (1 is weighted, as shown, and is provided with a pawl b, which engages with a circularor crown ratchet c, rigidly attached to the bottom of the chamber L, through which the stem d of the exhaust-valve projects. It will be seen that each time that the link R raises the valvestem d the pressure of the pawl 12 against the ratchet 0 will tend to rotate said stem, and on the descent of the stem the pawl will slip past some of the ratchet-teeth and take a fresh hold I have found that this constant rotation of the valve-stem and valve prevents uneven wear of the valve upon its seat and thus prolongs its efiiciency. Any suitable rotating device will of course accomplish the desired results.

The next group of devices are those which relate to the operation of the air-pump and V the admission of the charge into the cylinder.

The interior construction of the air-pump is of any ordinary character, and its piston is operated, as before stated, by the rod X. By referring to Fig. 2 it will be seen that the wrist-pin S, carrying the piston-rod of the air-pump, is placed in a radial slot in the disk D to permit adjustment of the stroke of the air-pump piston. It sometimes happens that an engine has 'but small duty to perform for weeks or months, and if the stroke of the pump is shortened to suit the requirements in such cases it will result in a lighter-running engine and a saving of gas. I am aware that this is a common device for many classes of machinery and a variety of pumps in general use; but I believe no gas-engine has ever been provided with a means of adjusting the charge constantly delivered by its pump/the usual method being to allow one or more reciprocations of the motor-piston without fresh charges. This last-mentioned system of regulation should only be applied to temporary or momentary charges of burden, as described farther on.

In Fig. 11, J is the end of the pump-cylinder, and 17 is the opening by which it draws in and expels its charge. This charge is composed of mingled gas and air, the gas coming through the supply-pipe Y and the air coming in at the opening 20. (Shown at the bottom of Fig. 11.) I V The valve system which controls the entrance of the two components will now be described. The opening 20 is at thebottom of a vertical chamber 11, which is perfectly cylindrical in form. The upper end of this chamber communicates with a horizontal passage-way 8, the opening'between them being so formed as to constitute a valve-seat for the valve 9. This valve 9 is hollow or tubular, as shown,and has at its upper end a vertical guiding-stem 10, by which its upward movement is limited, the limitation being regulated by a set-screw 19, arranged above the end of the stem 10. I prefer to construct the stem 10 in a separate piece from the valve 9, and let it seat itself in the central opening of the valve 9; but I also provide notches in that portion of the stem which is in contact with the valve 9, so that a free passage-way is left from the tubular interior. Each time that the pump draws in a charge the valve 9 is raised and air flows in by the passage 20 into the passage 8. I accomplish the admission of gas at the same time, but without direct communication with the air-inlet, in the following manner: \Vithin the cylinder 11, I mount so as to leave an annular space between them a second hollow cylinder 12. The gas-inlet pipe Y communicates with the interior of said cylinder 12, near whose bottom is a peripheral seat 13. Upon the valve-seat 13 the lower end or stem 15 of the valve 9 rests, so that when said valve 9 is in its lowest position the opening 13 is closed. The hollow stem 15 of the "alve 9 has near its lower end a series of radial or lateral openings, which are shown clearly in the sectional view of Fig. 13. A bushing 26 is arranged within the cylinder 12 for the stem 15 to slide in, and the bushing has in its lower portion an open annular space 16, surrounding the stem 15. About the middle of this annular space 16 is arranged a collar 14, having a series of vertical openings through it, as shown in Figs. 13 and 14. This collar is of such vertical height and so arranged that when the valve 9, and consequently the stem 15, are in their lowest position the collar 14 is opposite to and covers the whole orthe greater portion of each lateral opening in the stem 15; but when the valve 9 and stem 15 are raised said openings in the stem come opposite to the annular space 16 above the collar 1-4. Thus communication is established from the pipe Y, (when the stem '15 israised from the seat 13,) through the perforations of the collar'14, into the annular'space' 16 abovc the collar, thence through vare opened and closed by the movement of a single piece, and therefore in uniformity both as to time and relative extent of opening. Where the valves are separate or not coupled, it is found that they sometimes act irregularly, especially when the full charge is not being pumped. This is entirely avoided by my arrangement. The moment that the pump commences its back-stroke all these valves close instantly, and communication both with the gas and air supply is cutoff.

To insure a thorough commingling of the air and gas, I applyacross the'opening which leads from the passage. 8 to the inlet 17 of the air-pump a quantity of wire-gauze 18. The passage of the currents of air and gas through the meshes of the wire-gauze breaks up the stream'and causes an intimate mixture, and the operation is of course repeated upon the return-stroke of the pump, which forces the mixture into the motor-cylinder; Supposing the pump to have drawn in its charge of air and gas through the combined valve system whichhas just-been described, the return-stroke of the pump closes said system of valves and forces the mixture of air and gas along the-passageway 8 to the valve 1), which controls the opening n, into the motor-cylinder. This valve is lifted by the pressure beneath it and falls as soon as the pump. has completed its stroke, thus cutting off the egress of the mixture from the motor-cylinder. Said valve 19 is provided with a pawl-and-ratchet device '5 1", attached to its stem 19 and case, respectively,-and similar to that previously described in connection with the exhaust-valve 2f, the object being, as before stated, to cause the continuous slow rotation of the valve.

The most prominent feature of improvement inthe group of devices just described is the peculiar construction of the double valve by which gas and air are admitted through the same general inlet, but without coming in contact until actually within the main passage-way of the machine.

The next feature of improvement relates to the governing devices. Beneath the pumpcylinder J I arrange-a second cylinder or receptacle N, of about the same cubic capacity as the pump-cylinder, and establish communication between the pump-cylinder Jand said cylinder N (which I term the overflow-cylinder) by means of a pipe P. In this pipe P, which is shown in the detail view of Fig 15, is a balanced valve 21, turned by means of the connecting-rod g, which is attached to the lever 77., operated by the governor K;

.WVhen the balls of the governor move outward,

the lever h pulls the connecting-rod g, so as to open the 'valve 21. When, on the other hand, the balls move inward, the lever it pushes the. connecting rod g and closes the valve. Supposing the pump at this time to be in operation, if the speed of the apparatus is too great, the action of the governor K upon the valve 21 permits the discharge of the whole f or a portion of the pumps contents into the overflow-cylinder N, since the mixture from the pump finds a more ready exit through the pipe P than it does through the inlet p of the motor-cylinder. The motor-cylinder is thus left without any new charge of air and gas,

and no ignition takes place therein, so that the-momentum of the fly-wheel alone continues the action of the engine. Should the omission of a single chargein the motor-cylinder thus brought about beinsufficient, wever, to reduce the speed of the engine, the balls of the governor still remain in their outward position and the valve2l in the pipe P still remains open, so that on the return-stroke of the pump no new charge of air'and gas is drawn in through the main inlet of valves therefor; but the contents of the overflow-cylinder are merely drawn back again, and so long as the condition of too great speed exists in the engine the pump would merely continue to draw its charge from and redeliver it into the overflow cylinder. In practice, however, the operation cannot continue, since the speed of the engine is immediately reduced by the failure to supply fresh charges to the motor-cylinder, so that the action of the governing devices soon closes the valve so far as is necessary to maintain a uniform speed, and the normal action of the pump is resumed,

supplying a fresh charge at each reciprocaor accidental variations of burden upon-the engine, while the more permanent adj ustment of the charges is preferably effected by means of the radially-adjustable"wrist-pin t in the disk D, as before stated.

' I claim 1. In combination with the compressionchamber of a gas-engine cylinder, an inletduct leading thereto near its rear end and an outlet arranged upon the same side of the chamber and between the inlet and the piston, the line of projection of the inletrduct being suchas to strike the opposite side of the chamber or cylinder, whereby when the charge is admitted before the completion of the exhaust the identity of the entering and outgoing currents is maintained, substantially in the manner set forth.

. whereby as said spindle moves the said supplemental ports are opened in advance of the opening of the main port, substantially as set forth.

4. The combination, with the supplemental inlet-port leading into the ignition-chamber, of the perforated plate arranged over the opening of said inlet-port, whereby backing of flame is prex'ented and the entering ourrent is broken up to avoid direct impingement upon the igniting device.

5. The combined gas and air inlet consisting of a hollow valve the exterior periphery of whose head rests upon a seat formed in the air-channel and the bottom of whose stem rests upon a seat in the gas-channel, said stem being provided with lateral openings, and which lead into a chamber of the gaschannel above said last-mentioned seat, and said chamber being provided with a perforated ring fitting closely around the valvestem and of such vertical height as to control the lateral openings of the stem, the whole combined and operating substantially as set forth.

' JAS. DOXVNER SMITH.

Witnesses:

'IHos. M. SMITH, GEO. A. VAILLANT.

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